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There may be a problem with the power supply or a control board inside the printer. Since putting one new fuser did not cure the indication, that's a reasonable supposition.
Of course, before calling for servicing - or, replacing the printer perhaps - you should at least try turning Off the printer for at least 2 hours, to cool off and reset thoroughly, with it unplugged from the power for that duration.
Then see whether it comes up without the error. If the error persists, I would call for servicing - unless the maintenance kit is in the least bit dubious, or if it came without instructions on how to put it in properly, etc.
Let me know and I will advise you further as needed and as appropriate.